Seaweeds are important source of -

Seaweeds are macroscopic, multicellular marine algae that grow in the ocean. They are considered an exceptionally rich and natural source of Iodine. Iodine is a crucial trace element required by the human body for the synthesis of thyroid hormones (thyroxine and triiodothyronine), which regulate metabolism, growth, and development.

Marine algae, particularly brown seaweeds like kelp (Laminaria), have the unique ability to concentrate iodine from seawater, often reaching levels significantly higher than the surrounding environment. Historically, iodine was first isolated from the ash of burnt seaweed. While seaweeds also contain other minerals like potassium, magnesium, and calcium, they are most notably recognized in biological and nutritional contexts as a primary source of iodine. Argon is an inert noble gas, while chlorine and bromine, though halogens present in marine environments, are not the primary nutrients for which seaweeds are commercially or biologically harvested.